added an identity operator
added an identity operator

chaffra/sympy,wyom/sympy,Davidjohnwilson/sympy,sahmed95/sympy,MechCoder/sympy,mcdaniel67/sympy,mafiya69/sympy,jerli/sympy,liangjiaxing/sympy,mcdaniel67/sympy,kumarkrishna/sympy,kaushik94/sympy,iamutkarshtiwari/sympy,farhaanbukhsh/sympy,aktech/sympy,VaibhavAgarwalVA/sympy,abloomston/sympy,bukzor/sympy,Curious72/sympy,ga7g08/sympy,beni55/sympy,maniteja123/sympy,pbrady/sympy,grevutiu-gabriel/sympy,sahilshekhawat/sympy,moble/sympy,AunShiLord/sympy,AunShiLord/sympy,liangjiaxing/sympy,rahuldan/sympy,kumarkrishna/sympy,vipulroxx/sympy,souravsingh/sympy,pandeyadarsh/sympy,Davidjohnwilson/sympy,madan96/sympy,chaffra/sympy,grevutiu-gabriel/sympy,toolforger/sympy,emon10005/sympy,postvakje/sympy,postvakje/sympy,cswiercz/sympy,kaichogami/sympy,atsao72/sympy,lindsayad/sympy,kaushik94/sympy,abloomston/sympy,sunny94/temp,hargup/sympy,meghana1995/sympy,atreyv/sympy,lindsayad/sympy,Shaswat27/sympy,saurabhjn76/sympy,jaimahajan1997/sympy,skidzo/sympy,souravsingh/sympy,jaimahajan1997/sympy,ChristinaZografou/sympy,Arafatk/sympy,kaichogami/sympy,jbbskinny/sympy,sahilshekhawat/sympy,skirpichev/omg,MridulS/sympy,pandeyadarsh/sympy,drufat/sympy,hargup/sympy,AunShiLord/sympy,atsao72/sympy,debugger22/sympy,Vishluck/sympy,abhiii5459/sympy,oliverlee/sympy,ahhda/sympy,emon10005/sympy,VaibhavAgarwalVA/sympy,Designist/sympy,mafiya69/sympy,Shaswat27/sympy,aktech/sympy,rahuldan/sympy,jamesblunt/sympy,vipulroxx/sympy,debugger22/sympy,AkademieOlympia/sympy,AkademieOlympia/sympy,atreyv/sympy,shikil/sympy,MechCoder/sympy,atsao72/sympy,Gadal/sympy,jerli/sympy,abloomston/sympy,shikil/sympy,Vishluck/sympy,jamesblunt/sympy,yukoba/sympy,sunny94/temp,ahhda/sympy,sahilshekhawat/sympy,lindsayad/sympy,MechCoder/sympy,diofant/diofant,jbbskinny/sympy,saurabhjn76/sympy,yukoba/sympy,saurabhjn76/sympy,pandeyadarsh/sympy,toolforger/sympy,jerli/sympy,yukoba/sympy,farhaanbukhsh/sympy,abhiii5459/sympy,ga7g08/sympy,jamesblunt/sympy,asm666/sympy,Gadal/sympy,rahuldan/sympy,wanglongqi/sympy,Arafatk/sympy,wanglongqi/sympy,kaichogami/sympy,cccfran/sympy,pbrady/sympy,sampadsaha5/sympy,sahmed95/sympy,bukzor/sympy,jaimahajan1997/sympy,asm666/sympy,Mitchkoens/sympy,drufat/sympy,mafiya69/sympy,kevalds51/sympy,Sumith1896/sympy,yashsharan/sympy,cswiercz/sympy,debugger22/sympy,postvakje/sympy,Mitchkoens/sympy,wyom/sympy,cccfran/sympy,atreyv/sympy,ChristinaZografou/sympy,madan96/sympy,maniteja123/sympy,shipci/sympy,MridulS/sympy,kevalds51/sympy,asm666/sympy,souravsingh/sympy,mcdaniel67/sympy,sahmed95/sympy,kumarkrishna/sympy,Titan-C/sympy,Sumith1896/sympy,Titan-C/sympy,oliverlee/sympy,vipulroxx/sympy,Gadal/sympy,ahhda/sympy,jbbskinny/sympy,VaibhavAgarwalVA/sympy,Shaswat27/sympy,sampadsaha5/sympy,abhiii5459/sympy,garvitr/sympy,yashsharan/sympy,oliverlee/sympy,cccfran/sympy,Curious72/sympy,AkademieOlympia/sympy,shipci/sympy,pbrady/sympy,beni55/sympy,Davidjohnwilson/sympy,ga7g08/sympy,sunny94/temp,madan96/sympy,liangjiaxing/sympy,iamutkarshtiwari/sympy,dqnykamp/sympy,hargup/sympy,garvitr/sympy,aktech/sympy,farhaanbukhsh/sympy,emon10005/sympy,yashsharan/sympy,garvitr/sympy,drufat/sympy,bukzor/sympy,Arafatk/sympy,dqnykamp/sympy,meghana1995/sympy,wanglongqi/sympy,sampadsaha5/sympy,Titan-C/sympy,maniteja123/sympy,Designist/sympy,Vishluck/sympy,chaffra/sympy,iamutkarshtiwari/sympy,toolforger/sympy,skidzo/sympy,MridulS/sympy,Sumith1896/sympy,Mitchkoens/sympy,grevutiu-gabriel/sympy,cswiercz/sympy,dqnykamp/sympy,meghana1995/sympy,kaushik94/sympy,beni55/sympy,shipci/sympy,shikil/sympy,Curious72/sympy,Designist/sympy,moble/sympy,kevalds51/sympy,wyom/sympy,ChristinaZografou/sympy,moble/sympy,skidzo/sympy